Snagging a High Fly Ball

Snagging a high fly ball

Perseids Live! Balloon Flight Planned

Aug.
6, 1999: At the height of the baseball season, NASA is going
to stretch deep into the outfield to catch bits of a falling
star. But it'll be a night game, in the wee hours of Aug. 12
or 13 (next Thursday or Friday) when the Perseids meteor stream
is high in the sky.

The outfield is big, but the mitt and the fly balls are small,
so NASA is counting on quantity and a little luck to snare one
or two. Web viewers at home will get a chance to see the more
impressive fireballs, glowing as if they were hot line-drives.

The Perseids Live! balloon flight to about 33.5 km (110,000
ft) altitude will be NASA/Marshall's third mission to capture
materials of cosmic origin before they are incinerated by entry
into Earth's atmosphere or contact with the ground if they survive
entry.

NASA/Marshall's first two flights were in November 1998 during
the Leonids meteor shower and April 1999 during a meteor minimum
to provide a proper comparison. On Perseids Live!, NASA/Marshall
will continue experimenting with several types of capture media
to see how they fare at high altitude, and with new equipment
for tracking and imagery.

"We'll be carrying a new 12-channel GPS
receiver and an astronomical-type CCD camera," said Ed Myszka,
an amateur radio operator who has conducted a number of balloon
launches. Myszka works for CSC at NASA/Marshall's Science and Technology Directorate.

GPS - the Global Positioning System - uses timing signals
from satellites in high Earth orbit to calculate the receiver's
position. The 12-channel system should measure the Perseids Live!
balloon's horizontal location to within 100 meters (328 feet)
and its altitude to within 152 meters (500 ft).

"That's within the size of a football field," Myszka
said. "That's fairly good accuracy."

The payload will also include a new charge-coupled device
(CCD) camera, an electronic retina similar in some basic respects
to the Wide Field Camera aboard the Hubble Space Telescope.

Image above is one
frame of meteor recorded from the balloon (approx 3:32 a.m. CST
Nov 17, 1998) Click for 131KB animated gif

In the Southeast, tune to channel
58 on a cable-ready TV, connected to an antenna

"This
one was designed for use at the eyepiece by amateur astronomers,"
Myszka said. "We added a lens to give a wide-angle view."

The camera is more sensitive to light than the camera carried
on the two previous missions, and has about double the resolution.
Web viewers should have a better view of background stars and
bolides - meteors' fiery trails - than on the two earlier missions.

The radio downlink, power supply, and other equipment are
taken from the earlier missions. The transmitter also will be
the same and will broadcast on channel 58 for cable-ready TV
using an external antenna. This will be a line-of-sight signal
that can only be received in the Southeast.

The payload itself will use a larger frame, 20x20x72
cm (8x8x28 in). That in turn will allow more room for capture
devices. Several different materials, which will be selected
presently, will be tested for their ability to withstand the
trip to the edge of space (at about 18 km/hr [1,000 ft/minute])
and back, and a total duration of two hours.

The area-time product - 480 square centimeters for 2 hours
- is comparable to that of a 1965 sounding rocket flight [a brief
exposure with a larger sample area] which failed to return any
detectable Leonid meteoroids.

Myszka said that the balloon package probably will not travel
as far as the two previous balloons did.

"It will probably return to Earth closer to us,"
he said, "because the winds aloft have shifted as compared
to the November 1998 and April 1999 launches." He anticipates
landing will occur within 50 km (about 30 mi) of Redstone Arsenal
where NASA/Marshall is located.